Heating unit



Patented Dec. 18, 1928.

UNITED "STATES PATENT; OFFICE,

nimnsr E. SU'IHEBLAHD AND FRANK F. FORSHEE, OF MANSFIELD, OHIO,ASSIGNORS OF PENNSYLVANIA.

MANUFACTURING COMPANY, A CORPORATION HEATING UNIT.

Application mo e neptember 9, 1927. Serial in. 218,405. 7

Our invention "relates to electric heating units and more particularlyto base plates therefor. a m M object of our invention is tosgirovide arelatively simple, inexpensivean easily manufactured heating umt. I

Another object ofour invention is'to provide a single-piece base-plateembodying side supporting-portions for a refractory resistorsupportingmemher, laterally extending end portions embodying, respectivel a handleportion and a terminalwassem ly locatingu means, together with a centraldepressed heatpreferab y sheet steel, and embodies two parshieldportion. l a; 1

In practicing our invention, we provide a unitary 'base plate made .ofpressed sheet metal and embo ying spaced side portions located in acentral horizontal plane for directly sn porting a refractory plate,laterally exten g end portions, the

intermediate parts of "whiehiare bowedup- .wardl one end portion beingprovided with r a hen 1e and the other end portion being provided withslots for locatinga terminal-pinsupporting plate, and a centraldepressed portion constituting a. heat shield for the heating Theunitary; base plate alsolaterally extending inte a1 supporting portionsfor engaging suit le supporting members for the heating unit. I v p Inthe single sheet of drawings? Figure 1 is a top plan view of a baseplate embodying our invention with a refractory plate, shown in partonly, located thereon,

heating unit embodying ourinvention,

Fig. 3 is a fragmentar view, in elevation from the handle amigo ,theheating unit, and

assembled heating volition.

An ,eIectric heating -unit 11.; embcdies one a plurality ofoverhunggrooves in itsupper surface for receiving a helically woundresister 15. Asthe plate itself constitutes no part of our invention,ibis not deemed neces unched' and.

Fig. 2 is a view, in end elevation, of a end portions 0 the member 19with the inter- Fig. 4 is a view,in side elevatiom oi 8.11 unitembodyingv our insary to illustrate and describe it in further detaiL 7.Heretofore, relatively heavy cast-metal frames have. been :used as thesupporting members for, one or more of the refractory plates 12, butasupporting base plate made of cast metal must be made relatively heav1n order to obtain suificient' strength with the result'that the framewill have a relatively large heat-storage capacity.

The supporting base plate, more particularly embodying our invention, ismade 01 a single ieceo relatively thin sheet metal,

provided with a depending outer flange 23 to constitute a handle bymeans of WlllCll the heating 1111113 maybe moved into and out of itsnormal operative position relatively to a device, or appliance, to beheated thereby.

The intermediate portion 22 of the other end member 19 is locatedinsubstantially the same upper plane asgis the portion 21 andconstitutes a terminalspin-protecting memher. The inte ral sidewalls-connecting the mediate portion 22are each provided with slots 24which extend laterally of the heating unit, substantially asshown inFig. 1 of the drawings. I I

The member 13 embodiesalso a central depressed portion 25 constituting aheat shield and located in a lower plane than that of the side portion16. Openings 26 and 27 are provided in the sheet-metal plate incidentalto the punching and shaping portion necessary to change a flatsheet-metal plate tothe form shown in the drawing. The slots or openings26 and 27 extend laterally of the member 13, and, therefore. parallel tothe end portions'18-and19; Itis obvious that all the side walls of theupwardly bowed portions 21 and 22 must be of substantially the samelength as are the side walls of the central portion 25 and'the formingdie, or dies, are

so made that when the end portions are bentupwardly and the centralportion is bent downwardly, this requirement ofsuhstantial equality inlength of the side walls will be met. The depressed portion 25 is boweddownwardly toward the central point in order that itshall not buckleduring expansion or contraction oftlieinmnl'nr 18 in-ei.

dent to heating and cooling.

In order to provide inwardly extending lug portions, designated by 28and29, respectively, the side wall portions ot'ythepart is punched out-bysuitable means to the shape shown more particularl-y in-Fig. 1 oftheirictoryplate as well. The elongated form.

otthe openings is made necessary by the fact that refractory plates arenot exactly uniform but vary because of slightly changing conditionsduring their; manufacture.

The side-portions 16 andl7jhave depend ing flange port-ions 37 which, inturn, are each provided with outwardly:extending portions 38. Theportions 38 are, inturn, provided with a relatively narrow dependingflange portions 39 which are ada ted'to restupon suitable supports, suchas g ides, provided in the even of electric ranges; By providing theflange portions 39 with an elongated recess l1, illustrated moreparticularly in Fig. A ofthe drawings. there will be but four points ofsupport for the assembled heating element when located in its properoperative position on the supporting glides. The portions 37 may beprovided with elongated openings 42 therein in order'to reduce theamount ofheat. which will traverse the portions .37and the portions 38and'which might flow from there to the. supporting means.-

l heterminal assembly lat embodies a sheetmetal plate 43, ofsubstantially L-shape, in lateral section, one leg of which is bolted.against the under surfaceofthe intermediate portion 22 by a pluralityofshort screws .44 and nuts 4.5. A plurality of terminal pins 46 areinsulatedly mounted on the other leg of the member l3. in amannerwellknown in the art. As shown in the drawings, three suchterminal pins are provided to which the ends of the resistor wire 15 areconnected in order that a three-heat operation may be effected by asuitable switch (not shown), in a manner well known in the art. Theterminal pins 46 extendasuitable distance beyond the outer edge of theportion 22, in order that they may extend into cooperating socketmembers (not shown) which are connected to a suitable source. of su plyof electric energy.

The device emllodying our invention thus provides a sheet-metal baseplate having portions thereof located in three differentparallelwemftumling ilmwfl, certain portions of the plate being bentupwardly and another portion ofithe plate being bent downwardly.

The downwardly-bent central portion consth.

tutes a heat shield to reduce the ainount ot'. heat Whichisradiateddownwardly from the bottom of'the refractory plates 12. The slots, oropenings 24, provide. a convenient. means for receiving the endportionsof the terminal pinssupporting plate in ordeiw to hold it inproper alignment'latexally and longi tudinally of the heatingunit;

The device embodying our. invention thus. provides a singlepiecesheet-metal in se. plate forsupporting one or more refractoryplates.

of electric insulating material in which is mounted a resistor. A. plateofthis kind is relatively inexpensive aindhns a.relatively smallheatstorage. capacity.

Various-modifications may be made in; the device embodying our inventionwithout departing from tlre spirit and scope thereof and we desire,therefore, that only suchlimita' tions shall be placed thereon as areimposed by the. prior art-oi: are specifically setforth in the appendedclaims.

We claim as our invention:

1. An electric heating unitcomprising a. sheet-metal base platev bent tocomprise two spaced sidc-port'ionsanintegral cross mem ber at-oae endslrapml to constitute a han-v die, an integral cross'membemat theotherend bent to channel-shape, slote in the side walls of said cross memberof channel-shape, a termiIml-su-pporting but having its ends titty ting;into said slots, resistor operetively supported by the two sideport-ions only, and {germinal pins in said. terminal-supporting 9.Anelectric heatingunit comprising a refractory plate, a resistorsupported thereby, and a -base plate for supporting the refractory ates,said base plate comprising two paralel-extending side portions fordirectly operatively engaging the refractory plate, integral endport-ions bent upwardly from the plane of the side portions and mmbody-mg respectively a handle portion at-one end and aterminal-pinsupporting and protectingportion at the other end, and anintegral heatshield bent downwardly from the plane of the side portions.

3. An electric heating unit comprising a refractoryplate, a resistortherein, and a.

unitar sheet-metal base plate comprising a terminal-pin-supporting platehaving its two si e portions directly supporting the reends fitting intothe slots in one end portion. 10 fractory plate, two integral upwardlybowed In testimony whereof, we have hereunto end portions, one endportion having an insubscribed our names this 31st day of Aug.

5 tegral depending flange to constitute a han- 1927.

dle and the other end portion having slots in the side walls, and acentral downwardly- ERNEST E. SUTHERLAND.

bowed portion constituting a heat shield, and FRANK F. FORSHEE.

